Original Contribution
Prevalence of elevated blood pressure in 563 704 adult patients with stroke presenting to the ED in the United States

https://doi.org/10.1016/j.ajem.2006.07.008Get rights and content

Abstract

Purpose

The aim of this study was to estimate the prevalence of elevated blood pressure in adult patients with acute stroke in the United States (US).

Methods

Patients with stroke were classified by initial systolic blood pressure (SBP) into 4 categories using demographic, clinical, and treatment data from the National Hospital Ambulatory Medical Care Survey, the largest study of use and provision of emergency department (ED) services in the United States. We also compared the age-, sex-, and ethnicity-adjusted rates of elevated blood pressure strata, comparable with stages 1 and 2 hypertension in the US population.

Results

Of the 563 704 patients with stroke evaluated, initial SBP was below 140 mm Hg in 173 120 patients (31%), 140 to 184 mm Hg in 315 207 (56%), 185 to 219 mm Hg in 74 586 (13%), and 220 mm Hg or higher in 791 (0.1%). The mean time interval between presentation and evaluation was 40 ± 55, 33 ± 39, 25 ± 27, and 5 ± 1 minutes for increasing SBP strata (P = .009). A 3- and 8-fold higher rate of elevated blood pressure strata was observed in acute stroke than the existing rates of stages 1 and 2 hypertension in the US population. Labetalol and hydralazine were used in 6126 (1%) and 2262 (0.4%) patients, respectively. Thrombolytics were used in 1283 patients (0.4%), but only in those with SBP of 140 to 184 mm Hg.

Conclusions

In a nationally representative large data set, elevated blood pressure was observed in over 60% of the patients presenting with stroke to the ED. Elevated blood pressure was associated with an earlier evaluation; however, the use of thrombolytics was restricted to patients with ischemic stroke with SBP below 185 mm Hg.

Introduction

In 1981, Wallace and Levy [1] reported that blood pressure was elevated in 84% of the 334 consecutive admissions for acute stroke on the day of admission. There was spontaneous reduction of blood pressure (an average of 20 mm Hg systolic [SBP] and 10 mm Hg diastolic [DBP]) within 10 days following the acute event without any specific antihypertensive therapy, with only one third of the cases remaining hypertensive on the 10th day of hospitalization. Subsequently, several other studies [2], [3], [4], [5], [6], [7], [8] have also described elevation of blood pressure in the acute period of stroke. In a systematic review of 18 studies [9], 52% of the patients with stroke had elevated blood pressure at the time of admission. Further studies have evaluated the prognostic significance of the initial elevated blood pressure observed in patients with stroke [2], [3], [4], [5], [6], [7], [8]. Either lower or higher blood pressure after ischemic stroke and higher blood pressure after intracerebral hemorrhage were found to be associated with poor outcomes [5], [6]. Furthermore, elevated blood pressure among patients with intracerebral hemorrhage may increase the risk of hematoma expansion with subsequent neurologic deterioration [10], [11].

Recently, there has been renewed interest in the treatment of elevated blood pressure in acute stroke. Among patients with ischemic stroke, use of intravenous or intraarterial thrombolysis within 6 hours of symptom onset reduces death and disability at 3 to 6 months [12], [13]. Also, acutely elevated blood pressure increases the risk of thrombolytic-related intracranial hemorrhages in ischemic stroke and may require concomitant antihypertensive treatment [14], [15], [16]. However, optimal management strategies of elevated blood pressure in patients with acute ischemic stroke are unclear.

Before initiating further studies examining antihypertensive treatment strategies, it is necessary to define the magnitude of the problem. Most of the existing data addressing this issue are derived either from single-center studies or post hoc analysis of multicenter studies, which evaluated novel neuroprotective agents [2], [3], [4], [5], [6], [7], [8]. In such studies, the magnitude of the problem could not be evaluated because of variability in patient selection, study design, referral patterns, and the definition of elevated blood pressure. We therefore performed the present study to determine the national prevalence of elevated blood pressure in adult patients with stroke, using a nationally representative sample of the United States (US) population.

Section snippets

National Hospital Ambulatory Medical Care Survey

We used the data from the National Hospital Ambulatory Medical Care Survey (NHAMCS). The NHAMCS is designed to collect data on the use and provision of ambulatory care services in hospital emergency departments (EDs) [17], [18], [19] using a national probability sample of visits in noninstitutional general and short-stay hospitals in the 50 states and the District of Columbia. A total of 663 hospitals were selected for the NHAMCS sample. Within the ED, 100 patient visits were systematically

Results

Of the 563 704 adult patients evaluated with stroke, SBP of 140 mm Hg or higher was observed in 63%, DBP of 90 mm Hg or higher in 28%, and mean arterial pressure of 107 mm Hg or higher in 38% of the patients. The proportion of patients with SBP 140 mm Hg or higher according to stroke subtypes was as follows: ischemic stroke (67%), intracerebral hemorrhage (75%), and subarachnoid hemorrhage (100%) (see Table 1). The proportion of patients with DBP of 90 mm Hg or higher or mean arterial pressure

Discussion

The present study, which is one of the largest to date, demonstrates that acutely elevated blood pressure was observed in over 60% of the patients presenting with stroke to the ED. The results are derived from settings that are representative of the nationwide admissions. Therefore, the study provides more meaningful data compared with single center studies or post hoc analysis of randomized trials. We found that high SBP was most prevalent in the acute period. Admission SBP in patients with

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